The present disclosure relates to systems and methods for treating subterranean formations.
Treatment fluids may be used in a variety of subterranean treatments. Such treatments include, but are not limited to, stimulation treatments. As used herein, the term “treatment,” or “treating,” refers to any subterranean operation that uses a fluid in conjunction with a desired function and/or for a desired purpose. The term “treatment,” or “treating,” does not necessarily imply any particular action by the fluid.
One production stimulation operation that employs a treatment fluid is hydraulic fracturing. Hydraulic fracturing operations generally involve pumping a treatment fluid (e.g., a fracturing fluid) into a well bore that penetrates a subterranean formation at a sufficient hydraulic pressure to create or enhance one or more cracks, or “fractures,” in the subterranean formation. The fracturing fluid may comprise particulates, often referred to as “proppant particulates,” that are deposited in the fractures. The proppant particulates function, inter alia, to prevent the fractures from fully closing upon the release of hydraulic pressure, forming conductive channels through which fluids may flow to the well bore.
In certain approaches, hydraulic fracturing may use a cross-linked polymer to increase the viscosity of the fracturing fluid. The relatively high viscosity of such a fluid may, among other benefits, help transport the proppant particulates to the desired location within the formation and/or allow the fracturing fluid to be loaded with a higher concentration of proppant particulates. Once at least one fracture is created and the proppant particulates are substantially in place, the viscosity of the fracturing fluid usually is reduced, and the fracturing fluid may be recovered from the formation. The treatment fluid that is recovered is known as a flow-back fluid.
An alternative type of hydraulic fracturing, known as slickwater hydraulic fracturing, does not use a cross-linked polymer. The fracturing fluid has a relatively low viscosity as a result. Slickwater fracturing may be used to generate a narrow, complex fractures with low concentrations of proppants. Because the viscosity of the fracturing fluid is relatively low, the proppant transport is achieved by increasing the pumping rate and pressure of the fracturing fluid. During pumping, significant energy loss can occur due to the friction between the fracturing fluid and the casing or tubing, particularly when the fracturing fluid is in turbulent flow.
A friction reducer is often included in the fracturing fluid during slickwater fracturing operations to minimize such energy consumption. The friction reducer is typically a non-cross-linked polymer. It facilitates laminar flow of the treatment fluid, which causes less frictional forces and energy loss than turbulent flow of the same fluid. Due to the chemical nature of the friction reducer, however, the friction reducer can potentially damage the formation if it is not appropriately treated and breaks into low molecular weight fragments. Therefore, it can be advantageous to track the concentration of the friction reducer in the treatment fluid and particularly the flow-back fluid.
While embodiments of this disclosure have been depicted, such embodiments do not imply a limitation on the disclosure, and no such limitation should be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and not exhaustive of the scope of the disclosure.